Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[KenC]

Hey all,

I just wanted to post my experience as a data point and get the group's thoughts on my theory. I have a 2020 model 3 AWD. My charging set up is a HPWC and I charge daily or every other day, with only 1 supercharging session ever. My daily commute used to be fairy short, about 20 miles round trip, and so the battery was typically between 50%-80% all of the time We took my wife's Y for long trips so the 3 has never really seen a long trip. The rated miles started around 310, and I honestly don't recall if I ever saw higher than that after the software bump. However, I did see a fairly sharp decline around 7000 miles on the odometer to a nadir of about 275 miles at 100% (projected at a charge of about 80%) I was mildly concerned about this but due to the car's use as above it wouldn't really affect me at all. Lately my daily commute has grown significantly to 108 miles round trip daily. With this, Ive seen a steady increase in my rated miles up to 305 miles today at 100% (projected).

The other interesting point is my efficiency used to be absurdly high (115-125%) that by stats put me better than 97% of users. With the increase in my rated miles, my efficiency has dropped to around 100%.

TLDR
1. With a large increase in my daily commute my rated miles have increased from 279--->305
2. Efficiency has dropped over this time as well


My question is could a very high efficiency be a clue that there are more rated miles than the battery meter is showing? I realize there are numerous factors affecting efficiency (driving style and weather) but it may provide an interesting data point for those who have low rated miles and are curious if it is a true reading or not

P.S. The weather did get much warmer from when the rated miles were 278 until 305 but I did not see the significant increase until my commute lengthened.

If you're basing this off Stats, know that their calculation of rated miles was temperature affected up until Jan of this year. Then they switched SOC apis so that the rated miles is no longer affected. So, did this change in commute and rated miles occur sometime in late January?

Here's my Stats rated miles, and it varied with the seasons, until end of January when the SOC api changed. Now it shows rated miles, regardless of temps.

 

[Jejunjm]

For sure some 2021 AWD non-P vehicles at least have that battery. But there is the additional question about what the maximum available energy is set to on those packs (which is relevant here and I have not seen a lot of info on). It seems like it is around 80kWh so far.

That is 1.5kWh lower than the Performance or so, and additionally the degradation threshold is certainly set differently for now (~77.8kWh vs ~80.6kWh).

Ahh. But a lower available energy is protective in terms of charging to 100 and discharging to 0?

 

[AlanSubie4Life]

Ahh. But a lower available energy is protective in terms of charging to 100 and discharging to 0?

Maybe. I guess based on the voltages we have seen in SMT, the bottom of the pack is where the energy is hidden (I don’t off the top of my head recall whether we have seen 403V for one of these packs (from you?), and what the available energy was at that point).

More buffer (some of which is completely inaccessible?) at the bottom is not that helpful for anything. At the top would be better since it helps regen but maybe there would be some slight impact on max HP if they did it that way. But anyway, the voltage is definitive there, so whatever the SMT captures say is what you get.

Another possibility is that Tesla is selecting lower initial capacity 82.1kWh packs for the LR. They may not have perfect process control. No idea. Only way to tell (that I can think of) is to look at voltage at 0% and 100% and do the same for a Performance.

 

[Trevor B]

On second thought, there is a third way: you could also just have the seller send you a recent screen shot of their phone, like this. Just make sure it is done at a relatively high SOC (in the example, this is done at 91% or so). This picture is captured by sliding the slider all the way to the right, HOLDING, and doing a screen capture (you're looking for the little white numbers within the green area (NOT the big numbers above the battery which show by default) which are the projection to 100% when the slider (the little triangle) is positioned at 100%). This vehicle shows 7% capacity loss (which is actually ~10%, but that is a detail...). You'd just like to avoid a vehicle that shows 260, or even 270 miles, at 100%, or at least use that fact to negotiate down the price if the seller is willing, since it actually does matter a little (6kWh is not nothing...):

Do not assume because the vehicle has only 5k miles on it that the battery will be in great shape (though it might be). It's approaching 3 years old, so you should expect capacity loss even if it has not been used.

Obviously you also have to confirm all this info for yourself, in the vehicle, before you pay for it.

View attachment 674089

Great idea. It shows 293 for me, is this normal?

I have the RWD, so it's looks like -10% after 15k miles.

 

[AlanSubie4Life]

Great idea. It shows 293 for me, is this normal?

I have the RWD, so it's looks like -10% after 15k miles.

Yep, sounds normal.

 

[cardsdoc]

I realize there is plenty of battery advice out there although unfortunately there is quite a bit of variability in recommendations.

My 2022 M3 LR is just over one week old. I have a relatively short weekday daily commute, round trip under 40miles. I have a Tesla wall connector at home. My plan was to plug in nightly with a charge limit of 70%, and set a weekday departure time as well which fits within Tesla’s recs and much advice out there. However I’m also reading that this practice may throw off battery calibration and estimated range (although not actual range). What would be the simplest way to maintain healthy charging habits yet keep range estimate fairly accurate. Do what I’m doing already and occasionally do a 100% charge and near full discharge? Thanks.

 

[nj1266]

Can someone explain the odd battery curve that my model 3 Performance has. This data is taken from Stats app. It starts with around 297 miles with a full charge which is normal given the 299 epa rating. Then it climbs high to above 315 which is not normal, then falls below 294 and now it has settled around 300.

 

[AlanSubie4Life]

Can someone explain the odd battery curve that my model 3 Performance has. This data is taken from Stats app. It starts with around 297 miles with a full charge which is normal given the 299 epa rating. Then it climbs high to above 315 which is not normal, then falls below 294 and now it has settled around 300. View attachment 676149

Sounds like you have a 2020. Did you change your wheel configuration to 18” wheels early on? (The avatar will tell you, I suppose.)

I guess it might be a 2021 and that jump was the software update to reflect the constant adjustment that Tesla did to match EPA.

Not sure which it is. You said 315 was not normal so I suspect the former (315 miles would be normal for 2021 - that is the EPA range).

. Do what I’m doing already and occasionally do a 100% charge and near full discharge? Thanks.

Yeah this seems fine. No worries.

 

[nj1266]

Sounds like you have a 2020. Did you change your wheel configuration to 18” wheels early on? (The avatar will tell you, I suppose.)

I guess it might be a 2021 and that jump was the software update to reflect the constant adjustment that Tesla did to match EPA.

Not sure which it is. You said 315 was not normal so I suspect the former (315 miles would be normal for 2021 - that is the EPA range).


Yeah this seems fine. No worries.

You nailed it. I did change my wheels and tires from 235/35/20 to 255/40/18 and I did that right at the 500 mile mark when the range jumped. Can you explain to me why that will impact battery range? Thanks. The car is a 2020 3 Performanc.

 

[AlanSubie4Life]

Can you explain to me why that will impact battery range? Thanks

It does not actually affect the battery capacity at all. What happened is that for 2020 Performance, Tesla allows there to be three different “constants” for the vehicle depending on wheel type.

So it just changes the units. It’s like talking about a property value in dollars vs. euros vs. pesos. The property has the same value regardless, but it is worth different amounts of each currency.

The 18” wheels give you the miles that have the least energy (since those wheels are the most efficient), so there are more of them (sort of like when paying in pesos, since they are smaller value units of currency).

Beyond that, you have typical capacity loss of about 8% (297 miles vs your max of 322(18in) - though perhaps your vehicle never quite made 322, since it may have never quite made 299 (20in)).

“Rated Miles” are just a unit of energy (not distance). You could change to rated kilometers and there would be more of them - because the rated kilometers contain less energy, but your pack energy does not change.

If you change your wheel type (on the screen, not in reality) to 20”, your “range” will “drop” to about 276-278 miles. But nothing has changed. You have to compare that “range” to the original ~297 value (never quite 299). Just different units.

 

[KenC]

Can someone explain the odd battery curve that my model 3 Performance has. This data is taken from Stats app. It starts with around 297 miles with a full charge which is normal given the 299 epa rating. Then it climbs high to above 315 which is not normal, then falls below 294 and now it has settled around 300. View attachment 676149

Seems like alan has answered the early spike part of your question. As for the post-8000 miles bump, would that happen to be after January of this year, because Stats changed the SOC api it uses in that time frame, so that the estimated range which used to be affected by temperature, is now not affected by temp. So, some vehicles showed a pop and then a relatively flattening. Could be what you're showing, then again, it may not.

 

[lasttojoinclub]

this just isnt factual. you cant use your own battery degradation just because your 3 for some reason behaves different. the average for 26k miles is around 462km of rated range.

Is there a formula you are using to calculate degraded range, or is there data available that can be used to infer? The average range you mention is what I am observing at 26k, so I am curious to know what it might look like at 50k, 75k, etc.

 

[Candleflame]

Is there a formula you are using to calculate degraded range, or is there data available that can be used to infer? The average range you mention is what I am observing at 26k, so I am curious to know what it might look like at 50k, 75k, etc.

You can see fleet averages if you get teslafi

 

[lasttojoinclub]

You can see fleet averages if you get teslafi

Thank you!

 

[Mark_Y]

Been trending down for a while ... finally went sub-200 wh/mile lifetime, with over 30,000 miles. 2018 LR RWD with 18" aero wheel caps. Mostly solo commuting with relatively little freeway driving. Not a hypermiler, but I do try to stay off the brake pedal and rely on regenerative braking Not much need for A/C or heating in San Diego.

 

[Rothgarr]

Been trending down for a while ... finally went sub-200 wh/mile lifetime, with over 30,000 miles. 2018 LR RWD with 18" aero wheel caps. Mostly solo commuting with relatively little freeway driving. Not a hypermiler, but I do try to stay off the brake pedal and rely on regenerative braking Not much need for A/C or heating in San Diego.

Dang! That’s amazing. I can’t get my lifetime average below 275 where it’s currently sitting at. (2019 LR AWD)

Though my Recurrent reports appear to indicate that everything is OK…

 

[Apprunner]

Been trending down for a while ... finally went sub-200 wh/mile lifetime, with over 30,000 miles. 2018 LR RWD with 18" aero wheel caps. Mostly solo commuting with relatively little freeway driving. Not a hypermiler, but I do try to stay off the brake pedal and rely on regenerative braking Not much need for A/C or heating in San Diego.

You're driving it wrong...it should be in the 350wh/mile range Kidding of course but my Performance 3 is averaging in the 340wh/mile range. I always think my daily allotment of charge should be used up as not to go to waste

 

[jaqueh]

Dang! That’s amazing. I can’t get my lifetime average below 275 where it’s currently sitting at. (2019 LR AWD)

Though my Recurrent reports appear to indicate that everything is OK…

Yep! My lifetime is at 280. I think 260-300 is the norm, not the exception.

 

[Jejunjm]

Below 200 is amazing - but now I see rwd so I get it. I'm proud of my fairly conservative highway driving 236 over 3k miles. (2021 lr). I wish rwd was still an option!

 

[TAfirehawk]

Question for all the great people here...

My daily commute in my new M3LR is taking about 80% of the battery (varies a couple % on the wind). Is it better to use the battery from 90% to 10% (not much cushion when weather gets colder in Texas) or use the battery from 100% to 20%?